Download or read book A Review of Imperfection Sensitivity of Stiffened Shells written by R. L. Citerley and published by . This book was released on 1984 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: A short history is related about how imperfections (i.e., deviations from the assumed theoretical form of a shell structure) came to be regarded as the major contributor to the experimental scatter observed in shell buckling tests, and the discrepancy between experimentally determined buckling loads and those determined by classical linear theory. J.M.T. Thompson's insight into the relationship between imperfection sensitivity and optimality of shell structures with respect to load configurations is brought out. The significant contributions to understanding elastic postbuckling behavior of thin stiffened shells and how this work relates to imperfection sensitivity are reviewed. The implications of this work and its applicability to current engineering design and analysis are assessed. The effects of geometric imperfections as well as those induced by boundary conditions or multiple load cases on the postbuckling behavior of shells are discussed. Added discussions by Profs. Singer and van Neut are also presented. (Author).
Download or read book Numerical Methods for Imperfection Sensitivity Analysis of Stiffened Cylindrical Shells written by Richard L. Citerley and published by . This book was released on 1986 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains documentation for four computer programs used in the imperfection sensitivity analysis of cylindrical shells. The four programs are based upon Donnell's equation for cylindrical shells. The formulation of each program is worked in detail so others may make modification. Input and output instructions, together with the program listings, are provided. This report is in two volumes. Volume I discusses the development and applications of the programs, and Volume II is the user's manual.
Download or read book Numerical Methods for Imperfection Sensitivity Analysis of Stiffened Cylindrical Shells Volume 1 Development and Applications written by and published by . This book was released on 1986 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains documentation for four computer programs used in the imperfection sensitivity analysis of cylindrical shells. The four programs are based upon Donnell's equation for cylindrical shells. The formulation of each program is worked in detail so others may make modification. Input and output instructions, together with the program listings, are provided. This report is in two volumes. Volume I discusses the development and applications of the programs, and Volume II is the user's manual. Keywords: Shell buckling; Structural mechanics; Imperfection sensitivity; and Computer codes.
Download or read book The Buckling Analysis of Imperfection Sensitive Shell Structures written by Johann Arbocz and published by . This book was released on 1980 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computer Programs for Imperfection Sensitivity Analysis of Stiffened Cylindrical Shells written by R. L. Citerley and published by . This book was released on 1986 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Postbuckling and Imperfection Sensitivity Analysis of Axially Stiffened Cylindrical Shells with Mode Interaction written by E. Byskov and published by . This book was released on 1979 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Methods for Imperfection Sensitivity Analysis of Stiffened Cylindrical Shells written by Richard L. Citerley and published by . This book was released on 1986 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains documentation for four computer programs used in the imperfection sensitivity analysis of cylindrical shells. The four programs are based upon Donnell's equation for cylindrical shells. The formulation of each program is worked in detail so others may make modification. Input and output instructions, together with the program listings, are provided. This report is in two volumes. Volume I discusses the development and applications of the programs, and Volume II is the user's manual.
Download or read book Imperfection Insensitive Thin Shells written by Xin Ning and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The buckling of axially compressed cylindrical shells and externally pressurized spherical shells is extremely sensitive to even very small geometric imperfections. In practice this issue is addressed by either using overly conservative knockdown factors, while keeping perfect axial or spherical symmetry, or adding closely and equally spaced stiffeners on shell surface. The influence of imperfection-sensitivity is mitigated, but the shells designed from these approaches are either too heavy or very expensive and are still sensitive to imperfections. Despite their drawbacks, these approaches have been used for more than half a century. This thesis proposes a novel method to design imperfection-insensitive cylindrical shells subject to axial compression. Instead of following the classical paths, focused on axially symmetric or high-order rotationally symmetric cross-sections, the method in this thesis adopts optimal symmetry-breaking wavy cross-sections (wavy shells). The avoidance of imperfection sensitivity is achieved by searching with an evolutionary algorithm for smooth cross-sectional shapes that maximize the minimum among the buckling loads of geometrically perfect and imperfect wavy shells. It is found that the shells designed through this approach can achieve higher critical stresses and knockdown factors than any previously known monocoque cylindrical shells. It is also found that these shells have superior mass efficiency to almost all previously reported stiffened shells. Experimental studies on a design of composite wavy shell obtained through the proposed method are presented in this thesis. A method of making composite wavy shells and a photogrametry technique of measuring full-field geometric imperfections have been developed. Numerical predictions based on the measured geometric imperfections match remarkably well with the experiments. Experimental results confirm that the wavy shells are not sensitive to imperfections and can carry axial compression with superior mass efficiency. An efficient computational method for the buckling analysis of corrugated and stiffened cylindrical shells subject to axial compression has been developed in this thesis. This method modifies the traditional Bloch wave method based on the stiffness matrix method of rotationally periodic structures. A highly efficient algorithm has been developed to implement the modified Bloch wave method. This method is applied in buckling analyses of a series of corrugated composite cylindrical shells and a large-scale orthogonally stiffened aluminum cylindrical shell. Numerical examples show that the modified Bloch wave method can achieve very high accuracy and require much less computational time than linear and nonlinear analyses of detailed full finite element models. This thesis presents parametric studies on a series of externally pressurized pseudo-spherical shells, i.e., polyhedral shells, including icosahedron, geodesic shells, and triambic icosahedra. Several optimization methods have been developed to further improve the performance of pseudo-spherical shells under external pressure. It has been shown that the buckling pressures of the shell designs obtained from the optimizations are much higher than the spherical shells and not sensitive to imperfections.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1974 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Buckling of Shells written by Ekkehard Ramm and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin shells are very popular structures in many different branches of engineering. There are the domes, water and cooling towers, the contain ments in civil engineering, the pressure vessels and pipes in mechanical and nuclear engineering, storage tanks and platform components in marine and offshore engineering, the car bodies in the automobile industry, planes, rockets and space structures in aeronautical engineering, to mention only a few examples of the broad spectrum of application. In addition there is the large applied mechanics group involved in all the computational and experimental work in this area. Thin shells are in a way optimal structures. They play the role of·the "primadonnas" among all kinds of structures. Their performance can be extraordinary, but they can also be very sensitive. The susceptibility to buckling is a typical example. David Bushnell says in his recent review paper entitled "Buckling of Shells - Pitfall for DeSigners": "To the layman buckling is a mysterious, perhaps even awe inspiring phenomenon that transforms objects originally imbued with symmetrical beauty into junk".
Download or read book Analysis of Welded Structures written by Koichi Masubuchi and published by Elsevier. This book was released on 2013-10-22 with total page 655 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analysis of Welded Structures: Residual Stresses, Distortion, and their Consequences encompasses several topics related to design and fabrication of welded structures, particularly residual stresses and distortion, as well as their consequences. This book first introduces the subject by presenting the advantages and disadvantages of welded structures, as well as the historical overview of the topic and predicted trends. Then, this text considers residual stresses, heat flow, distortion, fracture toughness, and brittle and fatigue fractures of weldments. This selection concludes by discussing the effects of distortion and residual stresses on buckling strength of welded structures and effects of weld defects on service behavior. This book also provides supplementary discussions on some related and selected subjects. This text will be invaluable to metallurgists, welders, and students of metallurgy and welding.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computerized buckling analysis of shells written by D. Bushnell and published by Springer Science & Business Media. This book was released on 1985-09-30 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the work performed by Lockheed Palo Alto Research Labora tory, Palo Alto, California 94304. The work was sponsored by Air Force Office of Scientific Research, Bolling AFB, Washington, D. C. under Grant F49620-77-C-0l22 and by the Flight Dynamics Laboratory, Air Force Wright Aeronautical Laboratories, Wright-Patterson AFB, Ohio under Contract F3361S-76-C-31OS. The work was completed under Task 2307Nl, "Basic Research in Behavior of Metallic and Composite Components of Airframe Structures". The work was admini stered by Lt. Col. J. D. Morgan (AFOSR) and Dr. N. S. Khot (AFWAL/FIBRA). The contract work was performed between October 1977 and December 1980. The technical report was released by the Author in December 1981. Preface Many structures are assembled from parts which are thin. For example, a stiffened plate or cylindrical panel is composed of a sheet the thickness of which is small com pared to its length, breadth, and stiffener- spacing, and stiffeners the thickness of which is small compared to their _ heights and lengths. These assembled structures, loaded in compression, can buckle overall, that is sheet and stiffeners can collapse together in a general instability mode; the sheet can buckle locally between stiffeners; the stiffeners can cripple; and a variety of complex buckling interactions can occur involving local and overall deformations of both sheet and stiffeners. More complex, built-up structures can buckle in more complex and subtle ways.
Download or read book Report written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Buckling of Bars Plates and Shells written by Don Orr Brush and published by McGraw-Hill Companies. This book was released on 1975 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Buckling of Stiffened Cylinders in Axial Compression and Bending written by James P. Peterson and published by . This book was released on 1969 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Buckling data review for stiffened cylinder failures during axial compression and bending.
Download or read book Stability Analysis of Plates and Shells written by and published by . This book was released on 1998 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
